A&P URINARY SYSTEM

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APURINARYSYSTEM

• Instructor Terry Wiseth

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Urinary Anatomy

• Kidney
• Ureter
• Bladder
• Urethra

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Functions of Urinary System

• Clears blood of waste products of metabolism
• Uremia
• accumulation of toxic levels of wastes in blood
• maintain normal
• H2O and electrolyte balance
• fluid volumes
• blood pressure
• body pH

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Kidneys

• Excretory Organ
• Intestine, Skin, Lungs
• Excretes
• N2 wastes
• Toxins
• H20
• Electrolytes

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Microscopic Structure

• Nephron
• unit of function
• 1.25 million / kidney
• Highly vascular
• 20 of blood pumped / min

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Functions

• 1) maintain fluid balance
• 2) maintain electrolyte balance
• 3) maintain acid-base balance
• 4) remove N2 wastes
• urea
• 5) synthesize prostaglandin's
• 6) influence rate of secretion of hormones
• ADH / Aldosterone

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Kidney Failure

• blood constituents cannot be held in normal
  concentrations

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Nephron Anatomy

• 1) Glomerulus
• Arterioles
• Bowmans Capsule
• 2) Tubule
• Proximal
• Loop of Henle
• Ascending
• Descending
• Distal
• Collecting

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Urine Formation

• Actions in forming urine
• 1) filtration
• 2) reabsorption
• 3) secretion

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Glomerular Filtration

• blood flows through glomerular capillaries
• H2O and solutes filter out into Bowmans Capsule

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Glomerular Filtration

• blood flows through glomerular capillaries
• H2O and solutes filter out into Bowmans Capsule

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Glomerular Filtration

• pressure gradient causes filtration
• some kidney diseases
• permeability of glomerulus increases
• allows blood proteins to filter out into the
  capsule

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Glomerular Filtration

• High blood pressure in the glomerulus forces
  small molecules from blood into the Bowmans
  capsule

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Glomerular Filtration

• TEM of filtration slits from capillaries in
  Bowmans Capsule

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Glomerular Filtration

• Stress can lead to constriction of afferent
  arterioles
• causes filtration rate to lower
• and renal suppression kidney shutdown

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Glomerular Filtration

• glomerular filtration ratedirectly related to
  systemicblood pressure
• ? BP ? glomerular filtration
• ? BP ? glomerular filtration (slight)

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Tubular Reabsorption

• movement of substances from tubular fluid out to
  blood
• reabsorption from proximal convoluted tubules to
  blood

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Tubular Reabsorption

• movement of substances from tubular fluid out to
  blood
• reabsorption from proximal convoluted tubules to
  blood

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Tubular Reabsorption

• Glucose, amino acids, ions and other useful
  substances are actively transported from the
  tubule into blood

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Proximal Tubules

• Water follows passively by osmosis

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Glucose Reabsorption

• if blood glucose levels exceed threshold amount
  (150mg/100ml)
• not all glucose is reabsorbed

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Renal Diabetes

• congenital
• sometimes maximum transfer capacity is reduced
  and excess glucose appears in urine even though
  blood glucose level is normal

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Reabsorption from Loop of Henle

• Descending Loop
• Water diffuses out of the tubule by osmosis

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Reabsorption from Loop of Henle

• Ascending Loop
• Salts are actively transported out of the tubule,
  but water cannot follow because the walls of the
  tubule are impermeable to water

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Reabsorption from Loop of Henle

• NaCl is trapped in interstitial fluid of kidney
  medulla

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Reabsorption from Distal Tubules

• proximal tubules reabsorb 2/3 of Na
• distal tubules reabsorb 1/10 of Na

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Reabsorption from Distal Tubules

• distal tubules reabsorb H2O if antidiuretic
  hormone (ADH) is present

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Distal Tubule

• K, H and other ions, and certain large
  molecules are actively transported from the blood
  into the tubule, regulating the pH and ionic
  concentration of the blood

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Collecting Duct

• As the urine passes down the duct, water moves by
  osmosis from the duct into the blood

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Collecting Duct

• As the urine passes down the duct, water moves by
  osmosis from the duct into the blood

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ADH

• cause distal tubules to become permeable to H2O

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ADH

• small concentrated volume of urine is excreted

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ADH

• if no ADH in blood, then large volumes of urine
  produced (dilute concentration)

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Regulation of Urine Volume

• 1) ADH
• 2) Aldosterone
• 3) Extracellular fluid volume
• 4) Urine solute concentration

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Regulation of Urine Volume

• 1) ADH
• Presence
• decrease Urine Volume
• Absence
• increase Urine Volume

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Regulation of Urine Volume

• 2) Aldosterone
• increases Na reabsorption in distal tubule with
  H2O following

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Regulation of Urine Volume

• 3) urine volume relates directly to extracellular
  fluid volume (ECF)
• ECF ? urine volume ?
• ECF ? urine volume ?
• rapid ingestion of largeamount of fluid and
  resultingincreased ECF leads toincreased
  urinary output

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Regulation of Urine Volume

• 4) high solute concentration in urine increases
  urine volume by osmotic pressure
• untreated diabetes
• void large amounts of urine because excess
  glucose in blood spilling over

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Influence of Kidney on Blood Pressure

• Renal Hypertension
• decreased blood flow to kidney
• constriction of arterioles
• increased BP

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Ureters

• Tubes leading from kidney to bladder
• Urine moves by peristaltic movement

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Ureters

• Renal Calculi
• stones develop in kidney, washed out by urine
  into ureter
• distend ureter walls
• pain

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Bladder

• collapsible, elastic bag
• Ureters
• 2
• Bladder
• Urethra
• 1

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Functions of Bladder

• 1) reservoir for urine
• 2) expels urine
• distended causes sensation and desire to void

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Urethra

• passageway for eliminating urine

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Urethra

• passageway for eliminating urine

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Urine

• H2O
• 95
• N2 wastes
• Electrolytes
• Toxins
• Pigments
• Hormones

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Artificial Kidney

• Dialysis

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Artificial Kidney

• Dialysis

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Artificial Kidney

• continuous ambulatory peritoneal dialysis (CAPD)
• dialysis fluid administered to peritoneal cavity

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Kidney Transplant
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• END
• URINARY SYSTEM